I’ve been getting a lot of questions lately about Canon’s new 50-megapixel cameras, the 5DS and 5DS R. These models haven’t been released yet, but many Canon users are wondering whether they should upgrade.
Since these cameras aren’t available for testing yet, it’s hard to say anything definitive about them. But since I bought my 36-megapixel Sony A7r over a year ago I’ve learned a lot about working with high-resolution cameras, and some of those lessons might be relevant to people who are considering buying one of those new Canon models, or a 36-megapixel camera like the A7r, Nikon D800, or Nikon D810.
Do You Need All Those Megapixels?
First, if you’re considering buying one of these high-resolution cameras, can you really tell the difference between, say, 20 megapixels and 36, or 50? The answer is yes, absolutely – if you make a large print, and if you use sharp lenses and good technique with those high-res bodies. With my A7r, I can make 30×40-inch prints with all the detail I could want. Every blade of grass, twig, and pine needle is well-defined, even when you get right up to the print and look at it closely. And even in a 16×20 print the difference is noticeable, though obviously more subtle.
Of course, people don’t usually look at large prints closely. From five feet away, the difference between 20 megapixels and 36 might be discernible in a 30×40 print, but most people – even most photographers – wouldn’t notice.
So I love being able to create really sharp, large prints from my A7r. As a professional, I want to make the highest-quality prints I can. But most photographers never make large prints, or only make them occasionally for hanging in their office or on their living room wall, to be viewed by friends, family, and co-workers – people who won’t be inspecting the print from inches away to see how sharp it is.
So if you’re really picky about print sharpness, you should definitely consider buying a 36- or 50-megapixel camera. But honestly I think a 16- to 24-megapixel camera is probably more than enough for most photographers.
The Difference Between 36 and 50 Megapixels
If you’re still interested in one of these high-resolution cameras, will you be able to tell the difference between the 36-megapixel Sony sensors and the new 50-megapixel Canon sensor? Will the Canon produce sharper prints?
In theory, yes. With really sharp lenses, the higher-megapixel Canon should be able to make sharper prints than the Sony and Nikons. But as the number of pixels gets larger, and the photosites on the sensor get packed closer together, you need sharper lenses to resolve the difference between one photosite and the next. I suspect that you’ll be able to tell the difference only with some of the very sharpest lenses available today.
What About Noise?
You have to also consider noise. The more photosites you pack into the sensor, the smaller those sites have to be. Larger sites gather more light, which means the signal doesn’t have to be amplified as much, resulting in less noise. So all other things being equal, cramming more megapixels onto the sensor, requiring smaller photo sites, should result in higher noise.
But of course all things aren’t equal. Even at the pixel level, the Sony-made sensors in the D800, D810, and A7r have less read noise than the highest-resolution Canon bodies currently available, like the 5D Mark III (22 MP) and 6D (20MP). When you down-sample those 36 megapixel files from the Sony sensors to 22 megapixels, the difference is even greater.
So one of the biggest questions I have about the new 50-megapixel 5DS and 5DS R is about the noise levels. Canon says that the noise of the 5DS and 5DS R is about the same as the 5D Mark III at the pixel level. Since there are a lot more pixels in these new cameras, that should translate into less noise in the final print compared to the 5D Mark III.
But, of course, we only have Canon’s word on this so far, and will have to wait for actual tests. And the read noise at the pixel level of the Sony A7r, Nikon D800, and Nikon D810 is lower than the Canon 5D Mark III, so I suspect that the Sonys and Nikons will still outperform the new Canon when it comes to noise. We’ll see. (I compared the noise between the Canon 5D Mark III and Nikon D800 in this post.)
Lens quality matters with these cameras. This always makes a difference when you start making large prints, even with 16 or 20 megapixels. But a 36- or 50-megapixel sensor magnifies any lens flaws, and buying one of these cameras might show you just how bad your lenses really are.
That was certainly my experience. I’m not using any of the lenses that I owned 18 months ago. I’ve replaced my old Canon 70-200 f/4L with a much better copy. I’m also using that vintage Nikon 50mm f/1.8 lens that I talked about recently, and a very sharp Rokinon 24mm f/1.4 lens, which I bought for nighttime photography, but works well in the daytime also. And I’ve swapped my Canon 17-40 f/4L for a slightly sharper copy, though I plan to replace it with a better wide-angle zoom at some point.
I’m telling you this because if you really want the extra resolution from a 36- or 50- megapixel camera you may need to upgrade your lenses too. The center shouldn’t be a problem. Most professional-quality lenses, including zooms, are sharp enough in the center to take advantage of these high-resolution sensors. It’s the corners that separate the merely good lenses from the great ones. And when you’re looking at a print from a 36-megapixel camera, mushy corners really jump out at you when compared to a beautifully-crisp center.
I wish I could give you an easy formula for finding great lenses, but I haven’t found one. Just because a lens is expensive or has some fancy letters attached to its name (like L or ED) doesn’t mean it’s a great lens. Lens design is complicated. And even if the lens design is good, some copies are better than others. Also, I haven’t found much correlation between the online reviews and my real-world experience. All too often I’ll test a lens that has a great reputation, and gets good reviews from some of the lens-testing sites (DPReview, Photozone, DXO Mark, etc.), and find that it’s actually quite bad. Some of this is probably due to variations between copies, but I also think that the lab tests performed by these sites sometimes don’t translate into the real world. To me, the most useful online information comes from viewing actual full-size files made with the lens. But this only works when you can see all four corners in focus in the scene that was photographed for the test. It’s all too common to find lenses that are de-centered – softer on one side than the other, or even just soft in one corner – so seeing one corner isn’t enough.
Ultimately there’s no substitute for testing the lenses yourself. I’ve set up my own home-made lens-testing chart in my office, but unfortunately any set up like that only allows you to test lenses at relatively close focusing distances, and lens performance can change when you focus at infinity. So the best way to test lenses is to use them in the field. And make sure that when you buy a lens you can return it if you get a bad copy!
Having said all that, it’s sometimes possible to get good results with less-than-perfect lenses by understanding your lenses’ strengths and weaknesses. That means, first of all, knowing what aperture yields the sharpest corners at each focal length. And if the lens is de-centered you should know which side or corner is softest, so you can use the soft corners on the sky whenever possible. With 50 megapixels you could zoom out slightly, with the intention of cropping off the edges of the frame, and still have enough resolution to make beautiful large prints – though of course you wouldn’t be getting the full resolution and sharpness the camera is capable of.
There are also some software solutions that might be able to improve lens sharpness. There are no magic bullets here, but sometimes these can help. My favorite of these is Piccure+, which I plan to write more about soon.
High-resolution sensors also magnify any flaws in your technique. Of course you need to use a sturdy tripod with a cable release, remote, or self-timer. You should also lock up the mirror on DSLRs, and make sure image stabilization is off when you use a tripod.
In addition, tiny focusing errors become more noticeable with a 36-megapixel camera. If depth of field isn’t an issue (if everything is at infinity, for example, which happens fairly often in landscape photography), then autofocus can work, provided it’s calibrated properly. But probably the best way to ensure accurate focus is by zooming in with live view and focusing manually.
Depth of field also becomes more critical with high-resolution sensors, because a foreground or background that’s slightly out of focus becomes more noticable. I’m using focus stacking more often now with my A7r, and tilt-shift lenses could be useful also.
More megapixels = larger files = filling up hard drives really quickly. Plus you may start wishing you had a newer, faster computer with more RAM, as the bigger files can slow down Lightroom or Photoshop. I put a solid-state drive into my now four-year-old Mac laptop, and that helped immensely. But it may be time for a new computer soon.
It may sound like I’m trying to discourage people from buying a 36- or 50-megapixel camera. I’m not – believe me, I love mine. But you should know what you’re getting into.
And print sharpness isn’t the most important thing in photography. It might not even be on the top ten list. The image content – the light, composition, subject, and the emotional impact that those elements convey – is always far more important than how crisp the print looks when examined closely.
So I’m glad that Canon users will now have a high-resolution body available to them. And there are rumors about Sony and Nikon coming out with new 50-megapixel cameras (but so far just rumors). All that is great – the more options the better. But these cameras aren’t for everybody, and we should try to remember what really matters in photography.
— Michael Frye
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Michael Frye is a professional photographer specializing in landscapes and nature. He is the author or principal photographer of The Photographer’s Guide to Yosemite, Yosemite Meditations, Yosemite Meditations for Women, Yosemite Meditations for Adventurers, and Digital Landscape Photography: In the Footsteps of Ansel Adams and the Great Masters. He has also written three eBooks: Light & Land: Landscapes in the Digital Darkroom, Exposure for Outdoor Photography, and Landscapes in Lightroom 5: The Essential Step-by-Step Guide. Michael has written numerous magazine articles on the art and technique of photography, and his images have been published in over thirty countries around the world. Michael has lived either in or near Yosemite National Park since 1983, currently residing just outside the park in Mariposa, California.